In the Purim story, however, Haman isn't supposed to have been any more Persian than Mordecai is: He's an Amalekite, whom both Arabs and Jews consider Arabs.

As to the Samaritans, even speaking in purely biblical terms you have to look at the whole picture: The Assyrians deported SOME of the Israelites from their native lands, but not all, and, IMHO, probably not even most. Likewise, they brought in some tribes from other regions, but not a vacant land. Prompted by this thread, I hopped over to Wikipedia and read along as it reiterated what had been my understanding all along: The Samaritans to this very day consider themselves Israelites. What I didn't know is that genealogy appears to back them up on that: Scientific analysis of Samaritan DNA shows the presence of both identifiably Hebrew genes from at least the time of the Exile as well as genes from other peoples, leading scholars to conclude Israelite men "'married Assyrian and female exiles relocated from other conquered lands, which was a typical Assyrian policy to obliterate national identities.'[26]" and that "'Such a scenario could explain why Samaritan Y chromosome lineages cluster tightly with Jewish Y lineages, while their mitochondrial lineages are closest to Iraqi Jewish and Palestinian mtDNA sequences.'" Culturally, Samaritan religious leaders evidently hold that the split between themselves and other Jews occurred, not when the other ten tribes split from Judah and Benjamin (and made Samaria their capital) but when Eli made Shiloh the religious capital of Israel (at a time even before the first Israelite kings) so one might even say they consider themselves more Jewish than the Jews. I conceded in my last post that I didn't necessarily consider them Arab, but asserted that I DO consider them "Palestinian" in the modern sense of the word; I've long suspected Palestinians, as descendants of stateless Israelites and resettled peoples in Canaan under the Assyrians, are a lot more Jewish than Arab (and not Philistine at all) but it doesn't suit the politics of anyone involved to present it that way.

So, anyway, whether we're dealing with the Biblical tale of Isaac and Ishmael (Arab) or Mordecai and Haman (Arab) and whether those tales relate historical fact, fictional mythology or something in between, there are multiple stories of Jewish/Arab conflict from before there WAS European civilization, so it's hard to lay all the responsibility there.